An exemplary conventional control system 900 for irrigation management and control, which will be referred to here as a central-satellite system, is shown in FIG. 6A. The system 900 includes a central computer 902, a plurality of irrigation satellite field controllers (satellite controllers) 904, and a number of sensor data sources 906. The central computer 902 can be connected to the satellite controllers 904 by a first communication link 908 and to the sensor sources 906 by a second communications link 910. The first and second links 908, 910 can be wireless or wire line communication links of a local area network. The central computer 902 can include a user interface such as a keypad and a liquid crystal display so that a user can set up automatic watering programs, perform manual watering and perform additional functions for irrigation control.
The satellite controllers 904 can be connected to irrigation solenoid valves 912 to deliver water in accordance with the water programming or manual control. The sensor data sources 906 can monitor multiple variables that typically include the amount of rainfall, water flow and power consumption, and provide this data to the central computer 902 via the second communication link 910. The central computer 902 can distribute the data directly to the satellite controllers 904 so that the irrigation scheduling can be adjusted based upon the data. Alternatively, the central computer 902 can make the irrigation scheduling adjustments based on the data and distribute the adjustments to the satellite field controllers 904.
The central-satellite system 900 has the limitation of a costly architecture due to the requirement of multiple communication paths to be created and maintained between the central computer 902 and the satellite controllers 904. Further, in the central-satellite system 900 the number of sensor data sources is limited to the number of connections the central computer 902 can manage. Also, the central computer 902 must be used to gather and distribute data.
Another exemplary conventional control system 900′ for irrigation management and control, which will be referred to here as a peer-to-peer distributed network, is shown in FIG. 6B and described in U.S. Pat. No. 6,898,467 entitled “Distributed Control Network for Irrigation Management”, the contents of which are incorporated herein by reference. In this system 900′ the sensor data sources 906 are connected to dedicated sensor ports at the satellite controllers 904 via communication links 914. The system 900′ can further include a collection of individual sensors for providing a weather station connected via a data-logger to the central computer 902. The satellite controllers 904 and the central computer 902 are connected to the first communication link 908 of a peer-to-peer network. The first link 908 can be a communication bus. Although the peer-to-peer network connection between the satellite controllers 904 permits the sensor data to be shared among the satellite controllers 904, the number of sensor sources 906 is limited to the number of available sensor ports on the satellite controllers 904.